What is Air Break Switch : Working & Its Applications

An air switch is one kind of switch which is triggered by air. A push-button is used to activate a blow of air that moves through a PVC tube length to activate the air switch. The air switch is used to turn ON/OFF a device. These switches are frequently used wherever water is there although need to be kept away from electronics. The main advantage of using this air switch is to keep the operator away from the circuit components. This is helpful as it allows them to be utilized in wet locations without getting an electrical shock to the user. Air switches are available in different types like an air-break switch, isolators, earthing switches, load interrupter switches, and oil switches. So this article discusses one of the types of air switches namely the air break switch– working with applications.


What is Air Break Switch?

A type of switch which uses an air-like dielectric & arc quenching medium is known as an air break switch. So the contacts of this switch will open within the air. This switch is reliable and very effective as compared to other switches. This kind of switch is operated by hand once its handle is located on ground level. The air break switch diagram is shown below.

Air Break Switch
Air Break Switch

Here compressed air resolves the arcing problem which is occurred while operating this switch. The voltage range of these switches ranges from 450V to 35kV whereas the current range ranges from 800 A to 10KA. The air pressure used by these switches simply ranges from 4 to 60 atmospheres.

The air break switch working principle is; that this switch normally opens the circuit in the load. So, during the switch opening process, the arc gets generated is quenched in several ways by turning the contacts away from each other or by interrupting the supply.

Air Break Switch Construction & Its Working

This switch is constructed with different parts like a reservoir with compressed air, air blast valve, electromagnet, airline, arc blowout chamber, pistons, contacts, channels for gas escape, cylinder, piston, isolating switch contacts, airline, valve, and electromagnet.

In this switch, the contact’s opening & closing and the electric arc extinguishing are simply accomplished through compressed air. Here, the pressure of air within an air-break switch simply ranges from 0.4 to 6 MN/m2 (meganewtons per sq m) otherwise 4 to 60 (atmospheres).

Construction of Air Break Switch
Construction of Air Break Switch

The most commonly used pressures range from 16-40 atm or 1.6 – 4 MN/m2. The essential parts of this switch are; a reservoir including a compressed air supply, an arc extinguisher & an electro-pneumatic actuator. In air-break switches for up to 35 kV of currents, the arc extinguisher is arranged at the outside of the compressed-air reservoir & it is simply connected through an insulated airline.

The working of an air-break switch for currents up to 35 kV is; whenever the electromagnet in the above switch is de-energized, then the air-blast valve supplies compressed air from the compressed air reservoir through the air-line to the arc blowout chamber.

The compressed air which is performing on the pistons of the movable contacts pushes them away from the fixed contacts. Once the fixed contacts are opened, then an arc can be formed which is extinguished through the stream of compressed air and is being directed from the chamber with the help of the fixed contact outlets to the gas-escape channels which emit to the atmosphere.

After some delay time, the compressed air moves into the pneumatic actuator’s cylinder, then it activates the piston, breaks the isolating switch contacts once the arc is extinguished. After this, an air blast valve cuts off the incoming compressed air, and fixed contacts will be closed.

Similarly, when the electromagnet is energized, it simply opens the valve, then compressed air flows throughout the insulated airline & moves into the cylinder, where it shuts the contacts of isolating switch by performing on the piston.

Air-break switches at present are available in an enclosed isolating switch whose contacts are enclosed in an insulated casing that fills with compressed air upon disconnection. The switches at a minimum of 110 kV current & above up to 750 kV are simply manufactured through air-filled isolating switches.

Air Break Switch Types

These switches are classified into two types single-pole air-break switches & gang-operated air-break switches.

Single-Pole Air Break Switch

This type of switch is used to provide an opening for simply one conductor. So, the working of this switch is related to that of a typical air break switch.

Single Pole ABS
Single Pole ABS

Gang Operated Air Break Switch

A gang-operated ABS is mainly used whenever the opening of above one conductor is necessary at a time. In a gang-operated switch, the contacts will open within the atmosphere & quenching of a circular part achieves through packed air. Additionally, the air works as a dielectric mode for this switch.

Gang Operated ABS
Gang Operated ABS

As compared to other switches, this switch is dependable and runs physically once the handle is situated on ground level. These switches are introduced in two different methods either horizontally or vertically. These types of switches are mostly used for switching isolation purposes outdoor.

Air Break Switch Vs Disconnect Switch

The difference between an air break switch and a disconnect switch includes the following.

Air Break Switch

Disconnect Switch

The load switch is used to connect & disconnect some currents, normally with large values. The disconnect switch is used to switch a small current
It has a high breaking capacity. It has less breaking capacity.
It is switched in the load conditions. It is switched within no-load conditions.
This switch is composed of an arc extinguisher, an electro-pneumatic actuator, and a compressed air reservoir. Disconnect switches are normally composed of an actuator, an enclosure & wired electrical contacts.

Air Break Switch Vs Isolator

The difference between an air break switch and an isolator includes the following.

Air Break Switch

Isolator

This is an electrical switch, used to break the circuit within the air. An isolator is a mechanical switch that allows input and output isolation for a device within the open position.
These switches are mainly used for switching & isolation purposes. Isolators are mainly used for opening a circuit in no-load conditions.

 

These are available in two types single pole and gang operated. Isolators are available in different types like single break type, double break type, pantograph isolator, and MCB.
It is also known as the circuit breaker. It is also known as a disconnector.

Advantages

The advantages of an air break switch include the following.

  • As compared to normal switches, sir break switches are very efficient.
  • The consistency of these switches is much high.
  • These switches operate manually and also automatically based on the necessity.
  • It requires less maintenance and is also cheap.
  • These are capable of switching & fast breaker operations.
  • These types of break switches do not cause explosion & fire hazards.
  • This switch does not need a compressor.
  • By using these switches, the stability of the operation can be maintained.

Disadvantages

The disadvantages of air break switch include the following.

  • These switches are heavy in nature.
  • These switches are not applicable for modern power systems.
  • For the storage & production of compressed air, this kind of switch needs maximum capacity equipment.
  • The air has lower arc extinguishing properties.
  • There is a chance of air leakage which results in reduced pressure.
  • There are possibilities of a high rate increase of current chopping & re-striking voltage.

Air Break Switch Uses

The applications of air break switches include the following.

  • These switches are applicable in industrial as well as commercial applications.
  • These switches are installed outdoor for isolation & switching.
  • This switch is generally connected like a switching point within the distribution network.
  • This switch is used to stop the excitation current of a transmission line otherwise the capacitive charging current.
  • These switches are very useful for isolation & switching purposes.
  • These switches are used within power generation lines.
  • These types of switches offer essential point isolation in certain power distribution systems.
  • It is normally used to give short circuit & current protection.
  • These are utilized in industrial plants for different safety & control operations.
  • Generally, these switches are installed within the distribution networks like a switching point to connect or disconnect connections between transformers, cables & high voltage-based electrical devices.
  • These are connected to overhead power transmission lines.
  • These types of switches are mostly used to achieve ON/OFF switch by simply connecting the overhead line’s power system to the main distribution line otherwise by separating it from the major distribution line.
  • These switches allow the operator to separate an overhead line part without influencing the remaining part of the power transmission system.

Thus, this is all about an overview of air break switch – working, and its common uses. This is the most significant part of all overhead power transmission lines. The main function of the air break switch is to connect or disconnect the power system of a particular part of the Transformer & overhead line from the major distribution line. Generally, 11KV & 22KV type switches are used within power distribution lines whereas 33KV switches are used within power transmission lines & power generation. Here is a question for you, what is a circuit breaker?

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